Lashing arrangement for pusher towboat and barge



May 16, 1961 T. T. LUNDE LASHING ARRANGEMENT FOR PUSHER TOWBOAT AND BARGE Filed Jan. 6, 1958 2 Sheets--Sheei'I 1 INVENTOR. Tf'O//AS T LUNDE BYMW Afl-012212,15 v

T. T. LUNDE May 16, 1961 LASHING ARRANGEMENT FOR PUSHER TOWBOAT AND BARGE Filed Jan. 6, 1958 INVENTOR. THOMAS 7.` LUNDE ATTO/VEV Unite States atent (i)v G ARRANGEMENT FOR PUSHER TOWBOAT AND BARGE Thomas T. Lunde, 233 Cervantes Blvd., San Francisco, Calif.

LASHIN This invention relates to a method and apparatus for lashing a pusher vessel or towboat to a load-carrying pushed vessel or barge. The invention more particularly relates to a towboat-barge lashing arrangement which self-compensates for variations in barge freeboard and relative motion between the barge and towboat caused by wave action or loading and unloading the barge.

One object of this invention is to provide a lashing `arrangement that facilitates practical push-towing operations on rough bodies of water by self-compensating for relative motion between the towboat and barge imposed by wave action.

Another object of this invention is to provide a 1ashing arrangement which self-compensates for variations i'n barge freeboard as the barge is loaded or unloaded while pushing Contact between the barge and the towboat is maintained.

An additional object of this invention is to provide a lashing arrangement which self-compensates for unbalanced barge drag from bow to stern as the barge is pushed alongside a loading dock and is being loaded from bow to stern.

Still another object of this invention is to provide a lashing arrangement which permits a sudden and irregular unloading of barges with a rapid increase in freeboard but without requiring casting off and relashing and still maintaining control of the barge by the towboat.

Other objects of this invention will become apparent upon an understanding of the following description of an illustrative embodiment of the invention when considered in the light ofthe appended claims.

Heretofore, most push-tow operations have utilized towboats equipped with pusher knees located on the towboat bow as far off the centerline -as possible. These pusher knees `are usually vertical and bear on the stern headlog of the barge providing the pushing contact necessary to propel the barge. The towboat-barge lashing connections, consisting of chain or wire rope, are set up tight by means of turn-buckles or steamboat ratchets. Such a rigid lashing arrangement has functioned well on smooth water or in pushing barges of relatively fixed draft. However, this arrangement is not practically adaptable to push-tow operations on rough Water or where the barge freeboard varies any appreciable amount while towing, since the rigid towboat-barge lashing connections must continuously be adjusted.

On the other hand, in practicing the present invention it is possible to push-tow in four to five foot Waves and to maintain pushing contact with the barge as the barge is loaded and unloaded without adjusting the towboatbarge lashing connections.

In the drawings:

Fig. 1 is a schematic side elevational view of a selected embodiment of this invention showing an unloaded barge;

Fig. 2 is a schematic side elevational view indicating the same barge in its loaded condition;

r ICC Fig. 3 is a schematic top elevational view of the barge and towboat;

Fig. 4 is a side elevational view of the towboat pusher- PIPZ Fig. 5 is a front elevational view of the towboat pusher-pipe;

Fig. 6 is an exploded perspective view of the barge pusher-block;

Fig. 7 is a perspective view of the barge pusher-block engaged with the towboat pusher-pipe; and

Fig. 8 is a perspective view of a special towline tting.

Referring now specifically to Figs. l, 2 `and 3, a pusher towboat 1, of conventional design, is shown in pushing contact with a load-carrying barge 2, in its unladen condition in Fig. l and in its laden condition in Fig. 2 as illustrated by the relative freeboard indicated in Figs. l and 2, respectively. The waterline is represented by line 3i.

The lashing arrangement comprises, in general, a pusher-pipe 4 aixed to the bow of the towboat 1 which engages in sliding contact a pusher-block 5 mounted on the barge headlog, providing the pushing force necessary to propel the barge; and a pretensioned towline 6 which exibly maintains the contact between the towboat 1 and barge 2.

The towline 6 is a single length of strandedsteel wire rope with hemp center. It is connected at each end to a bitt 7 mounted on the starboard and port side, respectively, of the barge stern, and at the center to a power winch 8 located on the stern of the towboat 1. The connection to each barge bitt 7 is composed of a wire rope sling 9 looped over said bitt 7 and pinned to an axially loaded `coil spring 10 to which the end of the towline is attached. The towline 6 passes through a pair of single-pulley, quick-opening snatch blocks 11 mounted on each side of the towboat stern on a common transverse line, which impart changes of direction in the towline so as to position the middle thereof adjacent to the steam boat ratchets or winch 8. By means of wire rope clips 12, the middle of the towline 6 is looped around a specially designed tting 13, a perspective view of which is shown in Fig. 8. A steel centered wire rope 14 wound on the drum of the winch 8 also is fastened to fitting '13 by means of a pinned wire rope thimble 15.

By means of the Winch 8, the towline 6 may be tightened to any desired tension to eiect and maintain pushing contact between the towboat and barge; but, at the same time, the towline will retain an amount of llexibility that is a function of the resilience of the springs 10. In practicing a selected embodiment of this invention push-towing a single 5000 ton bottom dump barge, a, towline tension of 14,000 pounds was found to be satisfactory, at which tension the springs 10 were extended approximately half their allowable deflection.

The pusher-pipe 4 to which reference has been made is mounted on the towboat centerline by any suitable means, and is fabricated of rigid material, such extra heavy seamless steel pipe. The particular support means illustrated in Fig. 4 and Fig. 5 consists of support strut 16 and a structural steel frame 17 supported from conventional push-tow pusher knees 18 mounted on the towboat bow. This pusher-pipe 4 engages a pusher-block 5 mounted on the headlog of the barge and makes sliding contact therewith as the barge freeboard varies or as the barge and towboat pitch and roll.

The distinctive advantage of this lashing arrangement in self-compensating for relative motion between the towboat and barge as well as variations in barge freeboard is achieved mainly by locating the pusher-pipe 4 and, hence, the points of barge-towboat contact, so that the length of the lashing connections remains essentially constant; that is, the distance between the Ibarge bitts 7 and the pad eyes 19 mounted on a common transverse line on the towboat stern, to which the towline snatch blocks 11 are anchored, remains essentially the same for variations in barge freeboard. This is done in the illustrated embodiment by raking the pusher-pipe 4 aft slightly so that the points of contact between said pusher-pipe and the pusher-block 6 lfor maximum and minimum barge freeboard are each equidstant fro'm the center of the pad eyes 19. The pusher-pipe must be mounted so that the points of contact between it and the pusher-block for maximum and minimum barge freeboard, respectively, are each equidstant from the common transverse line on which pad eyes y19 are mounted.

l (if a straight pusher-pipe is used, it is apparent that for intermediate amounts of barge freeboard the distance between the barge bitt 7 land the snatch block pad eyes 19 will be somewhat less than for the minimum `or maximum freeboard. Slack in the towline 6 which would otherwise result is absorbed by the preloaded springs 10 inserted therein. Thus, when the barge is half-loaded, the pusher-pipe is normal to the plane defined by the forwardly extending towline. Alternately, as appears in Fig. 4, the pusher-pipe indicated as 4a may be curved to an `arc of a circle lying in a vertical plane containing the towboat centerline, the center of which is located at the point where a line connecting the centers olf the pad eyes .'19 intersects that plane. The resulting locus of the points of barge-towboat contact is then equidstant from the center of pad eyes i18 for any barge freeboard, and the towline springs 10 rather than absorbing slack in the towline are useful primarily for their cushioning effect. This latter effect of the springs is desirable with either pusher-pipe configuration.

The pusher-block is aiiixed to the barge headlog at the barge centerline and basically is comprised of two parts, a fixed plate 20 and a pivoted block 21, fabricated from steel plate or other sturdy material substantially as shown in fFig. 6. The cylindrically curved plate 20 mounted on a frame 22 is rigidly attached to the barge headlog. One side 23 of the pivoted block 21 has a cylindrically curved surface of the same radius as the exposed surface of the fixed plate 20 -and the surfaces are held in pivotal contact with each other by means of clips 24 plug welded to the frame f2.2. The opposite side 25 of the moveable block 21 is a cylindrically curved surface which engages the towboat pusher-pipe 4 and because of its curvature centers said pusher pipe on the barge centerline as pushing contact is maintained. The radius of curvature of the side 25 is much greater than the radius of curvature of the pusher-pipe 4. This design enables substantially line pushing contact to be maintained at all times between the pusher-pipe 4 and the pusher-block 5, even when there is a slight relative rolling between the tugboat and barge. As pushing force is applied to the moveable block 21 by contact with the pusher-pipe 4, the block 21 pivots on the fixed plate 20 and orients itself so as to present its surface 25 tangentially to the pusher-pipe 4, irrespective of barge freeboard or trim, or the angle of the pusher-pipe, as may be seen in Fig. 7.

l While what has been described hereabove is considered to be the preferred embodiment of this invention, it will be evident to those skilled in this Aart that various changes 'and modifications may be made without departing `from this invention. Therefore, this invention is not to be construed as being limited to the illustrative embodiment disclosed, but it is defined by the following claims.

I claim:

1. Apparatus for lashing a pusher towboat to a barge including a pusher towboat; a vertically extending pusher aixed to the bow of said towboat; a barge; a pusherblock affixed to the headlog of said barge to slidably receive said pusher; two bitts mounted near the stern of `said barge, dne of said bitts being to port and the other being to starboard; a first towline under tension and extending from said towboat to one of said bitts; and a second towline under tension and extending from said towboat to the other of said bitts; said towlines extending forwardly on said towboat from a common transverse line and said pusher having its points of contact with said pusher block for maximum and minimum barge freeboard each substantially equidstant from said transverse line.

2. Apparatus for lashing a pusher towboat to a barge including a pusher towboat; an aftwardly raked pusherpipe affixed to the bow of said towboat; a barge; a pusher-block aiiixed to the headlog of said barge to Slid- -ably receive said pusher-pipe; two bitts mounted near the stern of said barge, one of said bitts being to port and the other being to starboard; a first towline under tension and extending from said towboat to one of said bitts; a second towline under tension and extending from said towboat to the other of said bitts; and resilent means in each of said towlines; said towlines extending forwardly on said towboat from a common transverse line and said pusher-pipe having its points of contact with said pusherblock for maximum and minimum barge freeboard substantially equidstant from said transverse line.

3. Apparatus for lashing a pusher towboat to a barge including a pusher towboat; a pusher-pipe aiiixed to the bow of said towboat; a barge; a pusher-block affixed to the headlog of said barge to slidably receive said pusherpipe; a towline under tension and extending from the starboard stern quarter of said towboat to the starboard stern quarter of said barge; and -a towline under tension and extending from the port stern quarter of said towboat to the port stern quarter of said barge; said towlines extending forwardly on said towboat from a common transverse line and said pusher-pipe having its points of contact with said pusher-block for maximum and minimum barge freeboard substantially equidstant from said transverse line.

4. Apparatus for lashing a pusher towboat to a barge comprising: a pusher towboat; an aftwardly raked pusher pipe affixed to the bow of said towboat;

a first block mounted near the port stern quarter of said towboat; a second block mounted near the starboard stern quarter of said towboat;

winch means on said towboat; a barge;

a fixed plate affixed to the stern headlog of said barge at the centerline thereof;

a pivoted block embracing said pusher pipe and carried by said fixed plate and provided with a cylindrical curved pusher surface having a diameter in excess of the diameter of said pusher pipe;

a first bitt mounted near the starboard stern quarter of said barge; a towline under tension extending from said first bitt and around said first block to said winch means;

a towline under tensio'n extending `from said second bitt and around said second block to said winch means;

and resilient means carried by said towlines for maintaining said towlines under resilient tension.

5. Apparatus for lashing a pusher towboat to a barge comprising: a pusher towboat; an aftwardly raked pusher pipe aiiixed to the bow of said towbo'at; a barge;

a fixed plate aiiixed to the stern headlock of said barge at the centerline thereof;

a pivoted block embracing said pusher pipe and carried by said fixed plate and provided with a cylindrical curved pusher surface having a diameter in excess of the diameter of said pusher pipe;

a towline under tension and extending from the star- Iboard stern quarter of said towboat to the starboard stern quarter of said barge; and

a towline under tension and extending from the port stern quarter of said towboat to the port stern quarter of said barge.

6. Apparatus for lashing a pusher towboat to a barge comprising: a pusher towbo'at;

a pusher pipe afixed to the bow of the towboat; a barge;

a pusher block affixed to the head log of the barge;

a towline under tension and extending from the starboard stern quarter of said towboat to the starboard stern quarter of said barge; and

a seco'nd towline under tension and extending from the port stern quarter of said towboat to the port stern quarter of said barge;

said pusher pipe being disposed at an angle whereby it is normal to the plane dened by said towlines when said barge is half loaded.

7. Apparatus for lashing a pusher towboat to a barge comprising a pusher towboat; an aftwardly raked pusherpipe aflixed to the bow of said towboat; a barge; a pusherblock afxed to the headlog of said barge; two bitts mounted near the stern of said barge, one of said bitts being to port and the other to starboard; a iirst tow line under tension and extending from said towboat to one of said bitts; a second tow line under tension and extending from said towboat to the other of said bitts; and resilient means in each of said `tow lines; said pusher-pipe being -disposed at an angle whereby it is normal to the plane dened by said tow lines when said barge is half loaded.

8. Apparatus for lashing a pusher towboat to a barge comprising a pusher towboat; an aftwardly raked pusherpipe aixed to the bow of said towboat; a barge; a xed plate mounted on the stern headlog of said barge at the centerline thereof; a pivoted block embracing said pusherpipe and carried by said fixed plate and provided with a cylindrically curved pusher surface having a diameter in excess of the diameter of said pusher pipe; a tow line 6 l under tension and extending from the starboard stern quarter of said towboat to the starboard stern quarter of said barge; and a tow line under tension extending from the port stern quarter of said towboat to the port stern quarter of said barge; said pusher-pipe being disposed at an angle whereby it is normal to the plane defined by said tow lines when said barge is half loaded.

9. Apparatus for lashing a pusher vessel to a pushed vessel includingr a pusher vessel and a pushed vessel; line securing means for securing a line on said pusher vessel; a pusher having vertically spaced top and bottom ends afxed to one of said vessels and positioned whereby said ends are substantially equidistant from said line securing means when said vessels are longitudinally aligned with said pushed vessel forward of said pusher vessel; and means affixed to the other vessel to slideably receive said pusher.

l0. The combination of claim 9 wherein said pusher denes an arc substantially all points of which are radially equidistant from said line securing means when said vessels are longitudinally aligned as set forth.

References Cited in the tile of this patent UNITED STATES PATENTS 922,160 Lane May 18, 1909 1,509,012 Whiting Sept. 16, 1924 2,870,734 Armstrong Ian. 27, 1959 FOREIGN PATENTS 1,030,707 France Mar. 18, 1953 

